Variable redundancy data center power topology

ABSTRACT

A first power train that includes a first plurality of components, and a second power train includes a second plurality of components. The first power train is configured to provide power to a first plurality of server racks of a first data center at a first level of high-availability service associated with a first uptime. The first plurality of components includes a first subset of the first plurality of components and a second subset of the first plurality of components. The second power train is configured to provide power to a second plurality of server racks of the first data center at a second level of high-availability service that is associated with a second uptime that is less than the first uptime. The second plurality of components includes a first subset of the second plurality of components and the second subset of the first plurality of components.

BACKGROUND

The recent rise of online services has led a significant increase in thedevelopment, expansion, and improvement of data centers and similartechnologies. Such data centers may be used, for example, to providecloud computing services, facilitate popular social media services, orto provide infrastructure for e-commerce and other web sites.

A typical modern data center may include thousands, tens of thousands,hundreds of thousands, or more servers or other computing devices. Adata center may also include supporting equipment such as switches,routers, input/output equipment, temperature management equipment,and/or the like. A data center also typically includes equipment forpowering the computing devices and the supporting equipment.

SUMMARY OF THE DISCLOSURE

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter.

Briefly stated, the disclosed technology is generally directed to datacenter power topologies. In one example of the technology, an apparatusincludes a first power train and a second power train. In some examples,the first power train includes a first plurality of components. In someexamples, the first power train is configured to provide power to afirst plurality of server racks of a first data center at a first levelof high-availability service associated with a first uptime. In someexamples, the first plurality of components includes a first subset ofthe first plurality of components and a second subset of the firstplurality of components. In some examples, the second power trainincludes a second plurality of components. In some examples, the secondpower train is configured to provide power to a second plurality ofserver racks of the first data center at a second level ofhigh-availability service that is associated with a second uptime. Insome examples, the first uptime is greater than the second uptime. Insome examples, the second plurality of components includes a firstsubset of the second plurality of components and a second subset of thesecond plurality of components. In some examples, the second subset ofthe first plurality of components is the second subset of the secondplurality of components.

Other aspects of and applications for the disclosed technology will beappreciated upon reading and understanding the attached figures anddescription.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting and non-exhaustive examples of the present disclosure aredescribed with reference to the following drawings. In the drawings,like reference numerals refer to like parts throughout the variousfigures unless otherwise specified. These drawings are not necessarilydrawn to scale.

For a better understanding of the present disclosure, reference will bemade to the following Detailed Description, which is to be read inassociation with the accompanying drawings, in which:

FIG. 1 is a block diagram illustrating one example of a suitableenvironment in which aspects of the technology may be employed;

FIG. 2 is a block diagram illustrating one example of an apparatus for adata center;

FIGS. 3A-3C are a block diagram illustrating an example of the apparatusof FIG. 2;

FIG. 4 is a block diagram illustrating another example of an apparatusfor a data center;

FIG. 5 is a flow diagram illustrating an example of a process; and

FIG. 6 is a block diagram illustrating example hardware components of acomputing device, in accordance with aspects of the present disclosure.

DETAILED DESCRIPTION

The following description provides specific details for a thoroughunderstanding of, and enabling description for, various examples of thetechnology. One skilled in the art will understand that the technologymay be practiced without many of these details. In some instances,well-known structures and functions have not been shown or described indetail to avoid unnecessarily obscuring the description of examples ofthe technology. It is intended that the terminology used in thisdisclosure be interpreted in its broadest reasonable manner, even thoughit is being used in conjunction with a detailed description of certainexamples of the technology. Although certain terms may be emphasizedbelow, any terminology intended to be interpreted in any restrictedmanner will be overtly and specifically defined as such in this DetailedDescription section. Throughout the specification and claims, thefollowing terms take at least the meanings explicitly associated herein,unless the context dictates otherwise. The meanings identified below donot necessarily limit the terms, but merely provide illustrativeexamples for the terms. For example, each of the terms “based on” and“based upon” is not exclusive, and is equivalent to the term “based, atleast in part, on”, and includes the option of being based on additionalfactors, some of which may not be described herein. As another example,the term “via” is not exclusive, and is equivalent to the term “via, atleast in part”, and includes the option of being via additional factors,some of which may not be described herein. The meaning of “in” includes“in” and “on.” The phrase “in one embodiment,” or “in one example,” asused herein does not necessarily refer to the same embodiment orexample, although it may. Use of particular textual numeric designatorsdoes not imply the existence of lesser-valued numerical designators. Forexample, reciting “a widget selected from the group consisting of athird foo and a fourth bar” would not itself imply that there are atleast three foo, nor that there are at least four bar, elements.References in the singular are made merely for clarity of reading andinclude plural references unless plural references are specificallyexcluded. The term “or” is an inclusive “or” operator unlessspecifically indicated otherwise. For example, the phrases “A or B”means “A, B, or A and B.” As used herein, the terms “component” and“system” are intended to encompass hardware, software, or variouscombinations of hardware and software. Thus, for example, a system orcomponent may be a process, a process executing on a computing device,the computing device, or a portion thereof.

Briefly stated, the disclosed technology is generally directed datacenter power topologies. In one example of the technology, an apparatusincludes a first power train and a second power train. In some examples,the first power train includes a first plurality of components. In someexamples, the first power train is configured to provide power to afirst plurality of server racks of a first data center at a first levelof high-availability service associated with a first uptime. In someexamples, the first plurality of components includes a first subset ofthe first plurality of components and a second subset of the firstplurality of components. In some examples, the second power trainincludes a second plurality of components. In some examples, the secondpower train is configured to provide power to a second plurality ofserver racks of the first data center at a second level ofhigh-availability service that is associated with a second uptime. Insome examples, the first uptime is greater than the second uptime. Insome examples, the second plurality of components includes a firstsubset of the second plurality of components and a second subset of thesecond plurality of components. In some examples, the second subset ofthe first plurality of components is the second subset of the secondplurality of components.

In some examples, power may be provided in one data center with highavailability, with different levels of availability service fordifferent loads in the same data center. Availability is generallydefined as percentage uptime for a year. 99.9% uptime per year may bereferred to as 3×9 (8.77 hours of downtime per year), 99.99% uptime peryear may be referred to as 4×9 (52.60 minutes of downtime per year), and99.999% may be referred to as 5×9 (5.26 minutes of downtime per year).In some examples, power may be provided at a data center with 5×9availability for some servers in the data center, 4×9 availability forother servers in the data center, and 3×9 availability for yet otherservers in the data center.

The power for the data center loads may be provided by two or moredifferent topologies, one for each level of availability service, wherethe different topologies have components in common with each other. Forinstance, in some examples, there is one topology for 5×9 loads, anothertopology for 4×9 loads, and another topology for 3×9 loads, all in thesame data center, in which three different share components with eachother. For example, the topology for the 5×9 loads may share somecomponents with the topology for the 4×9 loads, the topology for the 3×9loads may share some component with the topology with the 4×9 loads, andthe topologies for all three loads may share some components with eachother.

Also, in some examples, the power from each of the different topologiesis selectively consumed on the downstream side by at least some of theloads.

Illustrative Devices/Operating Environments

FIG. 1 is a diagram of environment 100 in which aspects of thetechnology may be practiced. As shown, environment 100 includescomputing devices 110, as well as network nodes 120, connected vianetwork 130. Even though particular components of environment 100 areshown in FIG. 1, in other examples, environment 100 can also includeadditional and/or different components. For example, in certainexamples, the environment 100 can also include network storage devices,maintenance managers, and/or other suitable components (not shown).Computing devices 110 shown in FIG. 1 may be in various locations,including on premise, in the cloud, or the like. For example, computerdevices 110 may be on the client side, on the server side, or the like.

As shown in FIG. 1, network 130 can include one or more network nodes120 that interconnect multiple computing devices 110, and connectcomputing devices 110 to external network 140, e.g., the Internet or anintranet. For example, network nodes 120 may include switches, routers,hubs, network controllers, or other network elements. In certainexamples, computing devices 110 can be organized into racks, actionzones, groups, sets, or other suitable divisions. For example, in theillustrated example, computing devices 110 are grouped into three hostsets identified individually as first, second, and third host sets 112a-112 c. In the illustrated example, each of host sets 112 a-112 c isoperatively coupled to a corresponding network node 120 a-120 c,respectively, which are commonly referred to as “top-of-rack” or “TOR”network nodes. TOR network nodes 120 a-120 c can then be operativelycoupled to additional network nodes 120 to form a computer network in ahierarchical, flat, mesh, or other suitable types of topology thatallows communications between computing devices 110 and external network140. In other examples, multiple host sets 112 a-112 c may share asingle network node 120. Computing devices no may be virtually any typeof general- or specific-purpose computing device. For example, thesecomputing devices may be user devices such as desktop computers, laptopcomputers, tablet computers, display devices, cameras, printers, orsmartphones.

Various examples of the disclosure are employed in a data centerenvironment. In a data center environment, computing devices 110 may beserver devices such as application server computers, virtual computinghost computers, or file server computers. Moreover, computing devices110 may be individually configured to provide computing, storage, and/orother suitable computing services.

Illustrative System

FIG. 2 is a block diagram of an example system 201. System 201 mayinclude data center 260, network 230, and utility power feed 299. Datacenter 260 may include availability path 261, availability path 262,availability path 263, management layer 269, loads 271, loads 272, andloads 273. Availability path 261 may include components 251 andcomponents 252. Availability path 262 may include components 252,components 253, and components 254. Availability path 263 may includecomponent 254 and components 255.

In some examples, availability paths 261, 262, and 263 are arranged toreceive utility power from utility power feed 299. In some examples,availability path 261 is arranged to provide power to loads 271,availability path 262 is arranged to provide power to loads 272, andavailability path 263 is arranged to provide power to loads 273. In someexamples, some loads may be powered in a selectable manner, being drivenby a selected one of the availability paths based on existingavailability requirements. In some examples, the loads (271-273) mayinclude servers racks that includes servers. In some examples, the loads(271-273) are connected to network 230 for network communication.

In some examples, management layer 269 is configured to perform variousmanagement functions, such is determining how much load is beingconsumed by each of the availability paths 261-263, controlling transferof loads to the backup generator if an outage is detected in utilitypower, performing workload managements functions including shedding andreturning loads, management and control of switches including staticswitches and automatic transfer switches, opening and closing circuitbreakers, and/or the like. In some examples, the management layer mayinclude power meters, an electrical power monitoring system, or thelike, so that management layer 269 receives information about powerflowing through various parts of data center 260. In some examples,management layer 269 may communicate with network 230, and may performnotification or signaling into software, fabric controllers, and/orcloud services.

Some examples, management layer 269 may perform functions associatedwith power capping, workload management, and the control planes that runservers in the loads in conjunction with communication over network 230.In some examples in which there are loads that have selectedavailability, management layer 269 may determine an availability servicelevel for a load and perform control so that the load is driven inaccordance with the determine availability service level, as discussedin greater detail below.

Management layer 269 may also receive and use information such ascustomer demand, expected customer demand, power grid information suchas power levels and power prices, and/or the like.

As shown in FIG. 2, availability path 261 and availability path 262 havecomponents in common with each other in some examples. Similarly,availability path 262 and availability path 263 have components incommon with each other in some examples. Although not shown in FIG. 2,in some examples, all three availability paths 261, 262, and 263 havecomponents in common with each other in some examples. In this way, insome examples, different availability topologies are grouped togetherinto one datacenter in an efficient and cost-effective manner.

Availability paths may be different in some components due todifferences in the provided availability, while still having somecomponents in common. For instance, some availability paths may includea backup generator in order to provide greater availability, while otherpaths do not use a backup generator. Some availability paths may usedual corded servers with two PDUs in order to provide greateravailability, while other availability paths use single-corded serverswith one PDU. Some availability paths may use distributed redundancy toprovide alternate power sources under light loads conditions, whileother availability paths do not.

In some examples, availability path 261 is a 3×9 availability path,availability path 262 is a 4×9 availability path, and availability path263 is a 5×9 availability path. In some examples, availability path 261achieves 3×9 availability by using uninterruptible power supplies(UPSs), and using no backup generator, but rather running on batteryonly in the event of an outage. In some examples, availability path 262uses the aspects of availability path 262 that increase availability,and has still further availability using a backup generator anddistributed redundancy with alternate sources under light loadconditions. In some examples, loads can be changed during maintenance toan alternate source, or, responsive to an outage or failure occurring inone cell connected to one bus, power can be switched another bus thathas a cell with an alternate source.

In some examples, availability path 263 uses the aspects of availabilitypath 262 that increase availability, and has still further availabilityusing dual corded servers with each server rack in the load beingconnected to two PDUs and two sets of busways and dual power supplies inthe racks.

In some examples, availability paths that use a backup generator havelimited capacity relative what utility power feed 299 could otherwiseprovide, because utility power feed 299 provides more capacity than thebackup generator, but the backup generator must be able to backup theentire load in order to achieve the availability of the path thegreatest availability. In some examples, availability path 262 andavailability path 263 make use of a backup generator, but availabilitypath 261 does not. In this way, in some examples, the extra capacity ofutility power feed 299 beyond the capacity of the backup generator canbe assigned to availability path 261.

In some examples, by making use of this extra capacity, and using commoncomponents in the availability paths, different availability can beefficiently and cost-effectively provided in the same data center. Insome examples, this also allows different service availabilities to beprovide for different loads while correctly providing for capacityforecasting and carrying costs in a way that may otherwise beproblematic if the different availability loads were driven by entirelyseparate topologies.

As discussed above, in some examples, different availability servicelevels may be provided in selectable manner. In some examples, portionsof data center 260 may be composable in a late stage of construction, bymaking connections to compose the availability via small constructionchanges such as re-wiring one circuit panel to another circuit panel.

In some examples, assignment or reassignment of availability servicelevels can occur after construction. The assignment or reassignment ofavailability service levels after construction may be accomplished indifferent ways in different examples. For instance, in some examples,data center 260 may include at least one physical power panel or powerdistribution unit (PDU) that takes power sources from each of theavailability paths, and allow the power to be selectively consumed bythe loads. Also, in some examples, busways may be used, and a dynamicswitching device including circuit breakers, automatic transferswitches, static switches, and/or the like may be used to aggregate andmanage which availability paths are feeding downstream loads.

In some examples, the racks and the PDUs and the distribution of theracks may be part of the selection, where the racks themselves haveintelligence that may used in the selection. In various examples, theselection may be made at the PDU level, at the server rack busway level,or inside the server rack itself. In some examples, the server rack maybe connected, for example via PDUs, power panels, and/or busways to theavailability paths or to dynamic switching devices. Using the selectionmay prevent the need for maintaining an inventory of differentavailabilities and systems.

Although FIG. 2 shows an example of data center 260 that includes threeavailability paths, some examples include two availability paths, andsome examples include four or more availability paths. An example ofdata center 260 with two availability paths rather than three isdiscussed in greater detail below with regard to FIG. 4.

FIGS. 3A-3C are a block diagram illustrating an example of system 301,which may be employed as an example of system 201 FIG. 2. System 301includes data center 360, which may include cell A, cell B, and Cell C.Each cell (A-C) may include backup generator 341, transformer 342,uninterruptible power supplies UPS, automatic transfer switches ATS,static transfer switches STS, power distribution units PDU, and serverracks RACK.

In some examples, backup generator 341 is arranged to provide backuppower for 4×9 and 5×9 loads in the event of loss of utility power. Insome examples, logic in the management layer monitors the incomingpower, and sends a start signal to backup generator 341 if an outage isdetected, causing a transfer of the 4×9 and 5×9 loads to backupgenerator power. In some examples, the 3×95 are configured to run onbattery power in the event of a utility power outage, and the 3×9 loadswill drop if utility power has not returned by the time the batteriesrun out. In some examples, the topology for the 5×9 loads and thetopology for powering the 4×9 loads share the backup generator andcorresponding control as common components.

In some examples, transformer 342 is arranged to step down utilitypower, which may be medium voltage electrical campus distribution insome examples, into a lower voltage three-phase power. In some examples,static switches STS are high-speed components that transfer the loadsfrom one source to another without ever connecting the two sourcestogether and without dropping the load, so that no interruption isexperienced by the load.

In some examples, the three-phase power goes through the static switchesready to make a transfer is necessary. In some examples, if a faultcondition is detected, such as an undervoltage condition, anout-of-frequency condition, other power disturbance, or the like, theloads will transfer to an alternate bus to one of the other cells (e.g.,from cell A to cell B). The use of cells A, B, and C with switchingprovided by static switches STS is an example of distributed redundancy.In some examples, the topology for powering the 5×9 loads and thetopology for powering the 4×9 loads share the distributed redundancy ascomponents in common.

In some examples, ATSs move mechanical and building loads to analternate bus for an alternate cell in the event of an outage. In someexamples, the PDUs each include a transformer to transform the 480Vsignal to a 240V signal that the loads run at. In some examples, thePDUs for the 3×9 loads and the 4×9 loads each use one busway for provingpower to the loads in a single-corded topology. In some examples, forthe 5×9 RACK loads, there are two PDUs, two sets of busways, and dualpower supplies in RACKs. In some examples, the two PDUs, two sets ofbusways, and dual power supplies in RACKs act as components of thetopology for powering the 5×9 loads that is not shared by the topologyfor powering the 4×9 loads or the 3×9 loads.

In some examples, UPSs act as common components for the topologypowering the 3×9 loads, the topology powering the 4×9 loads, and thetopology powering the 5×9 loads. In and examples, the UPS and batteryfunctionality may exist in the servers or server racks.

In some examples, the topologies for providing power to a 5×9 load, 4×9load, or 3×9 load is selectable at the time of final installation, butremains fixed thereafter. In this way, in these examples, the equipmentis designed to select from availability paths, with loads selected atthe time of installation. In some examples, rather than loads beingfixed at the time of installation, additional switching is included indata center 360 such that the loads can be dynamically assigned orre-assigned on the fly, after installation, to be provided power as 5×9loads, 4×9 loads, or 3×9 loads.

FIG. 4 is a block diagram illustrating an example of data center 460.Data center 460 may include first power train 463 and second power train461. First power train 463 may include first plurality of components441. In some examples, first power train 463 is configured to providepower to a first plurality of server racks 473 of first data center 460at a first level of high-availability service associated with a firstuptime. First plurality of components 441 may include first subset 431of first plurality of components 441 and second subset 432 of firstplurality of components 441. Second power train 461 may include secondplurality of components 442. In some examples, second power train 461 isconfigured to provide power to second plurality of server racks 471 ofdata center 460 at a second level of high-availability service that isassociated with a second uptime. In some examples, the first uptime isgreater than the second uptime. Second plurality of components 442 mayinclude first subset 433 of second plurality of components 442 andsecond subset 431 of second plurality of components 442, where secondsubset 431 of first plurality of components 441 is second subset 431 ofsecond plurality of components 442.

FIG. 5 is a flow diagram illustrating an example of a process (580).

In the illustrated example, step 581 occurs first. At step 581, in someexamples, a first power train is employed to provide power to a firstplurality of server racks of a first data center at a first level ofhigh-availability service associated with a first uptime. In someexamples, a first power train includes a first plurality of components.In some examples, the first plurality of components includes a firstsubset of the first plurality of components and a second subset of thefirst plurality of components.

As shown, step 582 occurs next in some examples. At step 582, in someexamples, a second power train is employed to provide power to a secondplurality of server racks of the first data center at a second level ofhigh-availability service that is associated with a second uptime. Insome examples, the second power train includes a second plurality ofcomponents. In some examples, the first uptime is greater than thesecond uptime. In some examples, the second plurality of componentsincludes a first subset of the second plurality of components and asecond subset of the second plurality of components. In some examples,the second subset of the first plurality of components is the secondsubset of the second plurality of components.

The process may then proceed to the return block, where other processingis resumed.

Illustrative Computing Device

FIG. 6 is a high-level illustration of example hardware components ofcomputing device 600, which may be used to practice various aspects ofthe technology. For example, computing device 600 may be employed as oneof the computing devices 110 of FIG. 1, one of the servers of the serverrack load of FIG. 2, 3, or 4, and/or the like. As shown, computingdevice 600 includes processing circuit 610, operating memory 620, datastorage memory 630, input interface 640, output interface 650, andnetwork adapter 660. These aforementioned components may beinterconnected by bus 670.

Computing device 600 may be virtually any type of general- orspecific-purpose computing device. For example, computing device 600 maybe a user device such as a desktop computer, a laptop computer, a tabletcomputer, a display device, a camera, a printer, or a smartphone.Likewise, computing device 600 may also be server device such as anapplication server computer, a virtual computing host computer, or afile server computer.

Computing device 600 includes processing circuit 610 which may beadapted to execute instructions, such as instructions for implementingthe above-described processes or other technology. Processing circuit610 may include a microprocessor and/or a microcontroller and may serveas a control circuit. The aforementioned instructions, along with otherdata (e.g., datasets, metadata, operating system instructions, etc.),may be stored in operating memory 620 and/or data storage memory 630.

In one example, operating memory 620 is employed for run-time datastorage while data storage memory 630 is employed for long-term datastorage. However, each of operating memory 620 and data storage memory630 may be employed for either run-time or long-term data storage. Eachof operating memory 620 and data storage memory 630 may also include anyof a variety of data storage devices/components, such as volatilememories, semi-volatile memories, non-volatile memories, random accessmemories, static memories, disks, disk drives, caches, buffers, or anyother media that can be used to store information. However, operatingmemory 620 and data storage memory 630 specifically do not include orencompass communications media, any communications medium, or anysignals per se.

Also, computing device 600 may include or be coupled to any type ofcomputer-readable media such as computer-readable storage media (e.g.,operating memory 620 and data storage memory 630) and communicationmedia (e.g., communication signals and radio waves). While the termcomputer-readable storage media includes operating memory 620 and datastorage memory 630, this term specifically excludes and does notencompass communications media, any communications medium, or anysignals per se.

Computing device 600 also includes input interface 640 and outputinterface 650. Input interface 640 may be adapted to enable computingdevice 600 to receive information from a power monitor, power supply,power source, and/or other information source. Such information mayinclude an instantaneous power draw from a power source as well as anyof the other information mentioned in this disclosure. Output interface650 may be adapted to provide instructions to power supplies. Forexample, one such instruction is an instruction to a power supply toadjust a target DC output voltage. Output interface 650 may include aRS-232 interface, an I2C interface, a GPIB interface, and/or the like.

Computing device 600 also includes network adapter 660 which may beadapted to interface computing device 600 to a network such as network106. Network adapter 660 may include a network interface card (NIC), amedia access control (MAC) interface, a physical level interface (PHY),and/or the like. Network adapter 660 may also serve as an input and/oroutput interface for computing device 600.

CONCLUSION

While the above Detailed Description describes certain examples of thetechnology, and describes the best mode contemplated, no matter howdetailed the above appears in text, the technology can be practiced inmany ways. Details may vary in implementation, while still beingencompassed by the technology described herein. As noted above,particular terminology used when describing certain features or aspectsof the technology should not be taken to imply that the terminology isbeing redefined herein to be restricted to any specific characteristics,features, or aspects with which that terminology is associated. Ingeneral, the terms used in the following claims should not be construedto limit the technology to the specific examples disclosed herein,unless the Detailed Description explicitly defines such terms.Accordingly, the actual scope of the technology encompasses not only thedisclosed examples, but also all equivalent ways of practicing orimplementing the technology.

We claim:
 1. An apparatus, comprising: a first power train including afirst plurality of components, wherein the first power train isconfigured to provide power to a first plurality of server racks of afirst data center at a first level of high-availability serviceassociated with a first uptime availability, and wherein the firstplurality of components includes a first subset of the first pluralityof components and a second subset of the first plurality of components;and a second power train a including second plurality of components,wherein the second power train is configured to provide power to asecond plurality of server racks of the first data center at a secondlevel of high-availability service that is associated with a seconduptime availability, wherein the first uptime availability is greaterthan the second uptime availability, wherein the second plurality ofcomponents includes a first subset of the second plurality of componentsand a second subset of the second plurality of components, and whereinthe second subset of the first plurality of components is the secondsubset of the second plurality of components.
 2. The apparatus of claim1, wherein the first power train includes distributed redundancy, andwherein the second power train is powered by one power source only. 3.The apparatus of claim 1, wherein the first power train includes twopower distribution units and two busways for providing power to thefirst plurality of server racks in a dual corded topology, and whereinthe second power train includes one power distribution unit and onebusway for providing power to the second plurality of servers in asingle corded topology.
 4. The apparatus of claim 1, wherein the secondsubset of the first plurality of components includes a plurality ofuninterruptible power supplies.
 5. The apparatus of claim 1, wherein thesecond subset of the first plurality of components includes a pluralityof static switches that are configured to provide an alternate source ofpower via an alternate busway.
 6. The apparatus of claim 1, furthercomprising a control component that is configured to provide power to athird plurality of server racks based a selection between a plurality ofpower trains including the first power train and the second power train.7. The apparatus of claim 6, wherein the selection is a dynamicselection.
 8. The apparatus of claim 1, wherein the second subset of thefirst plurality of components includes a plurality of static switchesthat are configured to provide an alternate source of power via at leasttwo alternate busways.
 9. The apparatus of claim 8, the apparatusfurther comprising a plurality of cells including a first cell and asecond cell, each cell of the plurality of cells having at least twopower trains and at least two power distribution units, wherein a firstof the at least two alternate busways is a busway to the first cell, andwherein a second of the at least two alternate busways is a busway tothe second cell.
 10. The apparatus of claim 1, wherein the first powertrain includes a backup generator and control for transferring the firstplurality of server racks to be powered by the backup generatorresponsive to detection of a failure, and wherein the second power trainis configured to be powered by utility power only.
 11. The apparatus ofclaim 10, wherein the first power train is powered based on a capacityof the backup generator, and wherein the second power train is poweredbased on a difference between a capacity of the utility power and thecapacity of the backup generator.
 12. The apparatus of claim 1, whereinthe first uptime availability is a first uptime service level agreement,the second uptime availability is a second uptime level of service levelagreement, and wherein the first uptime service level agreement isgreater than the second uptime level service agreement.
 13. A method,comprising: employing a first power train to provide power to a firstplurality of server racks of a first data center at a first level ofhigh-availability service associated with a first availability ofuptime, wherein a first power train includes a first plurality ofcomponents, and wherein the first plurality of components includes afirst subset of the first plurality of components and a second subset ofthe first plurality of components; employing a second power train toprovide power to a second plurality of server racks of the first datacenter at a second level of high-availability service that is associatedwith a second availability of uptime, wherein the second power trainincludes a second plurality of components, wherein the firstavailability of uptime is greater than the second availability ofuptime, wherein the second plurality of components includes a firstsubset of the second plurality of components and a second subset of thesecond plurality of components, and wherein the second subset of thefirst plurality of components is the second subset of the secondplurality of components.
 14. The method of claim 13, further comprisingpowering at least one server rack based a selection between a pluralityof power trains including the first power train and the second powertrain.
 15. The method of claim 13, further comprising transferring thefirst plurality of server racks to be powered by a backup generator ofthe first power train responsive to detection of a failure, whereinpowering the second power train is accomplished by utility power only.16. The method of claim 15, wherein powering the first plurality ofserver racks is based on a capacity of the backup generator, and whereinpowering the second plurality of server racks is based on a differencebetween a capacity of the utility power and the capacity of the backupgenerator.
 17. An apparatus, comprising: a first data center including aplurality of topologies, wherein the plurality of topologies includes: afirst topology that is configured to provide power suitable for poweringserver loads in accordance with a first availability; and a secondtopology that is configured to provide power suitable for poweringserver loads in accordance with a second availability that is differentthan the first availability, wherein the second topology shares somecomponents in common with the first topology.
 18. The apparatus of claim17, wherein the first data center is configured to provide power to atleast one server load based on a selection from among the plurality oftopologies.
 19. The apparatus of claim 17, wherein the first topologyincludes a backup generator and control for transferring loads poweredby the first topology to the backup generator responsive to detection ofa failure, and wherein the second topology is configured to providepower based on utility power only.
 20. The apparatus of claim 19,wherein the first topology is arranged to provide power based on acapacity of the backup generator, and wherein the second topology isarranged to provide power based on a difference between a capacity ofthe utility power and the capacity of the backup generator.